A coupling of this general type has been disclosed, for example, in DE 42 05 666. This relates to a so-called articulated lever coupling in which levers pivoted between the drive and load are able to a certain extent to compensate for angular and axial misalignment of the connected elements. A shaft coupling created in this way also allows the radial misalignment of units to be compensated for whenever two couplings of the type described in DE 42 05 666 C2 are connected in series.
The links are supported in rubber bushings that have a damping function to a limited degree. In addition, rubber elements are required to provide angular positioning of drive and load relative to each other. They compensate for the change in spacing between the attachment elements of a link during rotation of the coupling.
Physical limits are placed on the possible angular and axial misalignment of two elements due to the requisite use of spacing-compensating rubber elements. In addition, the elastomer material also limits the maximum torque transmitted. In order to increase the torque load of the coupling, the coupling itself must be physically enlarged and the number of links used must be increased, which action in contrary fashion decreases the angular compensation capability of the coupling.
In order to be able to continue to bridge a defined radial misalignment between two elements given a reduced angular compensation capability, the shaft coupling must be physically lengthened.